Aromatic polysulphone-diphenyl sulphone blends

ABSTRACT

A thermoplastic composition is provided comprising (a) 90 to 99.99 percent by weight of at least one aromatic polysulphone consisting essentially of repeating units having the formulas I, II or III, either alone or in combination with each other and/or with up to 80 percent of units having the formula IV   and (b) 10 to 0.01 percent by weight of diphenyl sulphone.

United States atent [191 Hart et al.

[m ammo 1 Feb.27,1973

[ AROMATIC POLYSULPHONE- DIPHENYL SULPHONE BLENDS [75] Inventors:Charles Richard Hart, Hitchin,

Hertfordshire; Eric Nield, Wattonat-Stone, Hertfordshire; John BrewsterRose, Letchworth, Hertforshire, all of England [73] Assignee: ImperialChemical Industries Limited, London, England [22] Filed: June 10, 1971[211 App]. No.: 151,917

[30] Foreign Application Priority Data June 11, 1970 Great Britain..28,356/70 [52] 11.8. C1 ..260/30.8 R, 260/37 R, 260/857 R, 260/865,260/49 [51] Int. Cl. ..C08g 23/10 [58] Field of Search ..260/49, 79,30.8 R

[56] References Cited UNITED STATES PATENTS 3,549,595 12/1970 Campbell..260/49 3,558,740 1/1971 Behr et a1 ....260/823 3,565,862 2/ 1971Campbell et a1. ..260/49 3,579,475 5/1971 Jones et a1 ..260/37 PrimaryExaminerWilliam l-l. Short Assistant Examiner-L. L. Lee AttorneyCushman,Darby & Cushman [57] ABSTRACT A thermoplastic composition is providedcomprising (a) 90 to 99.99 percent by weight of at least one aromaticpolysulphone consisting essentially of repeating units having theformulas 1, 11 or III, either alone or in combination with each otherand/or with up to 80 percent of units having the formula IV and (b) 10to 0.01 percent by weight of diphenyl sulphone.

6 Claims, No Drawings AROMATIC POLYSULPHONE-DIPHENYL SULPHONE BLENDSThis invention relates to thermoplastic polymer com positions and inparticular to aromatic polysulphones and their blends having improvedprocessability.

Aromatic polysulphones and methods for making them are described inBritish patent specifications, Nos. 1016 245,1060 246,1078 234,1 109842,1 122 192,1133 561,1 153 035,1 153 528 and 1 177183 and GermanSpecification No. 2 038 168. They are generally thermoplastic materialsof high softening point and considerable resistance to chemicaldegradation even at high temperatures. Owing to their high softeningpoints, and generally rather high melt viscosities at even highertemperatures, however, specially adapted equipment is often required forfabricating them into shaped articles by moulding or extruding from themelt.

It has now been found that certain aromatic polysulphones and theirblends with other thermoplastic materials can be mixed with diphenylsulphone as processing aid to form compositions having a desirablecombination of physical properties. The mixtures of aromaticpolysulphones with diphenyl sulphone are usually tough materials havingbetter melt flow properties than the polysulphones themselves.

According to the present invention, a thermoplastic composition isprovided comprising (a) 90 to 99.99 percent by weight of at least onearomatic polysulphone consisting essentially of repeating units havingthe formulae 1, 11 or 111, either alone or in combination with eachother and/or with up to 80 percent of units having the formula IV,

and (b) to 0.01 percent by weight of diphenyl sulphone.

The compositions of the invention are preferably made by mixing diphenylsulphone with the molten for recording tapes), photosensitisers, and anyother materials for which the compositions of the invention makesuitable vehicles. The compositions may contain dyes and pigments. Thecompositions may be fabricated in any desired form, such as fiber, filmand mouldings or extruded products of any desired shape.

Incorporation of 0.01 to 10 percent by weight of diphenyl sulphonereduces the melt viscosity of the aromatic polysulphone and its blends,resulting in a more even distribution of physical properties in ameltprocessed article. Inclusion of quantities in excess of 10 percentby weight can lead to an unacceptable worsening in the desirablephysical properties of the composition, for example, softening point andimpact strength. In order to reduce the melt viscosity whilst stillmaintaining acceptable physical properties, a preferred proportion ofdiphenyl sulphone is from 0.01 percent to 5 percent by weight.

The invention is illustrated by the following example.

EXAMPlE An aromatic polysulphone consisting essentially of repeatingunits of the formula made in manner similar to that described in Example3 of specification No. l 153 035, and having a reduced viscosity of 0.43(measured at 25 C. on a solution in dimethyl formamide containing lgpolymer in cm of solution), was mixed with diphenyl sulphone. Thecomposition was prepared by mixing polysulphone (g) with diphenylsulphone (10g) in an extruder at 320 C. The extrudate was chipped,re-extruded and chipped and the chip compression-moulded at 330 C.Samples of the composition were compared with similar samples preparedfrom polysulphone alone and, as shown in the following table, the meltviscosity is reduced by 40 percent, whilst the Full Vicat softeningpoint and impact strength are reduced only by 16 percent and 19 percentrespectively.

The impact strength test was carried out at 20 C. on a specimen 51 mmlong, 6.3 mm wide, and 3 mm thick having a 45 notch, 2.8 mm deep (tipradius 0.25 mm) in the center of one edge. It was supported between twosupports 38 mm apart and struck centrally on the edge opposite the notchby a pendulum dropping from 305 mm with more than sufficient energy tobreak the specimen. From the residual energy of the pendulum, the energyrequired to break the specimen was calculated and divided by thecross-sectional area of the specimen at the notch. The resulting value(expressed in kJ/m) represents the energy required to break thematerial.

Polysulphone with Polysulphone 5% w/w Diphenyl alone sulphone Full Vicatsoftening point ("(1 1m 2|:

l/lO Vicnt wnenin point t" 1'12 )IU A min notched Impact strength (Id/m5.25 6.50

Apparent Modulus (dyne/cm 3.0 X l 2.7 X 10" Melt Viscosity at 1000 seeat 380C (kilopoisc) 1.7 2.8

For comparison, composition was prepared as above except that4,4'-dichlorodiphenyl sulphone (10g) was used in place of the diphenylsulphone. The results of physical tests shown in the following tableshow the in-' clusion of the additive is associated with a reduction ofonly 18 percent in the melt viscosity, whilst the impact strength isreduced by 47 percent respectively.

Polysulphone with Polysulphone w/w Dichlorodiphenyl sulphone Full Vicatsoftening point (C) 189 219 1/10 Vicat softening point (C) 180 210 4 mmnotched Impact Strength (kl/m 3.40 6.50 Apparent modulus (dyne/cm 3.0 X2.7 X 10" Melt Viscosity at 1000 sec at 380C (kilopoise) 2.3 2.8

A similar composition could be prepared from the aromatic polysulphonesconsisting essentially of repeating units having the formulae We claim:

1. A thermoplastic composition comprising:

a. from 90 to 99.99 percent by weight of at least one aromaticpolysulphone consisting essentially of repeating units having theformula I, ll or III, combinations of any such units with each other orcombinations of any such units with units of formula W, the units offormula IV not exceeding percent of (a):

b. from 10 to 0.01 percent by weight of diphenyl sulphone. 2. Athermoplastic composition according to claim 1 in which the aromaticpolysulphone consists essentially of repeat units having the formula 3.A thermoplastic composition according to claim 1 in which the diphenylsulphone is present in concentration 0.01 to 5 percent by weight.

4. A thermoplastic composition as claimed in claim 1 in the form of afiber.

5. A thermoplastic composition as claimed in claim 1 in the form offilm.

6. A thermoplastic composition as claimed in claim 1 in the form of amoulded article.

2. A thermoplastic composition according to claim 1 in which thearomatic polysulphone consists essentially of repeat units having theformula
 3. A thermoplastic composition according to claim 1 in which thediphenyl sulphone is present in concentration 0.01 to 5 percent byweight.
 4. A thermoplastic composition as claimed in claim 1 in the formof a fiber.
 5. A thermoplastic composition as claimed in claim 1 in theform of film.
 6. A thermoplastic composition as claimed in claim 1 inthe form of a moulded article.